There are some general recommendations to keep in mind when contacting your elected officials. In many offices you'll be reaching a staff person. The more local the representation the more likely you'll reach the official her/himself.
Let the staff person, or official, know you are a constituent. If appropriate you can also share your name, zip code and city.
Keep it brief! Whether you are writing or calling, a staff person or the elected official is probably dealing with other communications and work. Stick to one topic or issue that is of concern and if writing, keep it to one page.
Share your position or state your concerns. Be clear about what action you would like the elected official to take.
Choose your two or three most important points to share with the official.
Make it personal. If you have a relevant personal story share it. If you have a personal connection with the official, a mention of this might make them feel closer to you.
Be polite.